Calculus Rotations Help!!!!

Hello, I'm am really suck on these problems. If you're really smart I could use your help right now!

Use the disk method to find the volume of the solid:

y=2x-1, x=0, y=x^2 rotated about line y=3

Use the disk and shell method to solve this rotation:

y=-x^2+16, Y=16, X=4 about line x=2

Use either method to solve this rotation:

y=cos(x), y=sin(x), x=pi/4, x=5pi/4, about line x=5pi/4

Please help. I've been working on then for hours and have some equations but I don' know if they are right!(Crying)